Pressure atomizing liquid fuel burner with air stream centering ring



Aug. .18, 1959 R. w. BECKETT PRESSURE ATOMIZING LIQUID FUEL BURNER WITH AIR STREAM CENTERING RING Filed Oct. 31. 1956 II I I, I

INVENTOR Reginald (Beckett b Bowm,5w

am MM ATTORNEYS 0 United States Patent PRESSURE ATOh IIZING LIQUID FUEL BURNER WITH AIR STREAM CENTERING RING Reginald W. Beckett, Elyria, Ohio Application October 31, 1956, Serial No. 619,565

15 Claims. (Cl. 158-76) This invention relates to fluid fuel burners, more particularly to oil burners of the pressure atomizing type. My co-pending application for patent, Serial No. 152,353, filed March 28, 1950, now Patent No. 2,777,509, for Fluid Fuel Burner for Free Standing the Plate Mounting Installations, discloses burners of the type referred to. Such burners force the air for combustion through an internally smooth walled air tube of circular section, the fuel being discharged into the air at the outlet end of the air tube. characteristically, the air enters the receiving end of the air tube tangentially and advances in a spiral column so as to be discharged in the form of a rotating air mas that entrains the fuel and holds the latter in suspension during combustion. The rate at which air is advanced through the air tube and discharged into the combustion chamber is closely related to the rate at which the fuel or oil is released or sprayed into such air and one of the recognized problems of the industry is that a burner having an air tube designed to burn fuel efiiciently at one rate cannot be expected to function efficiently when the fuel or oil burning rate and consequently the air consuming rate is substantially altered.

The trade, however, demands burners standardized that will consume oil or fuel at vastly different rates depending upon the particular heat requirements of any given installation. Manufacturers ofburners are thus confronted with the problem of furnishing a single standard model or at least a limited number of models of burners which are capable of adjustment or modification at minimum cost to satisfy the trade requirements for widely varying fuel or oil consumption rates.

It is, therefore, one of the principal objects of the present invention to provide a burner of the character referred to which can be standardized for manufacture in quantity, yet can be readily and inexpensively modified in manufacturing to obtain proper and eflicient air delively for any desired oil rate over a relatively wide range. More particularly the invention provides an air tube structure comprising several components, certain ones of which have dimensional characteristics related to a particular oil rate of the burner and others of which are dimensionally standardized and are used with burners of different oil rates. 7

Another problem met in the operation of pressure atomizing oil burners is carbonization of fuel on the nozzle to which the fuel oil is supplied at high pressure and through which the fuel is projected into the combustion chamber. It has been recognized-that nozzle carbonization can be eliminated by keeping the nozzle at a relatively cool temperature and numerous expedients have been used for such purpose. Thus another of the objects of the present invention is to provide an air tube and fuel nozzle combination, in a burner of the character referred to, which effectively eliminates nozzle carbonization by deflecting uniformly an intermediate annular portion of the, spirally advancing air column radially inwardly so as to flow the air across not only the nozzle tip but also across the heavy sectional metal adapter body which is interposed between the nozzle and the fuel supply'conduit. The invention accomplishes this radial air deflection without destroying the characteristic spiral motion of the air and thereby obtains improved combustion characteristics in that the air turbulence is relatively increased in the center of the rotating air mass which is discharged from'the air tube, While the spirally advancing or rotating character of such air mass is maintained, these being further objects of the invention.

Another object of the invention is concerned with air tube structural refinements which achieve improved 'heat conduction away from the head and which also result in manufacturing economies through standardization of oil burner air tube assemblies and elimination of close control of dimensional characteristics of certain components. More specifically this aspect of the invention is concerned with the telescopic assembly of a' number of air tube components such, for example, as the main tubular body, the discharge head and the mounting base, the head and base being connected to the tubular body by telescopic joints. By allowing for variation in the axial length of one or both of the telescopic joints, it is feasible to make the head or base or both the head and the base inthe form of inexpensive stampings of, say, stainless sheet'steel and to make the air tube body of uniform circular section from end to end. As a further advantage of such a structure, using telescopic friction fit joints, the air tube body can be cut from a long length of stainless steel tubing, the length measurement not being critical since variations are accommodated in one or both of the telescopic end joints.

Control of the air column advancing spirally through the circular sectioned air tube and also deflection of an intermediate portion of the air column to flow radially inwardly across the nozzle and the nozzle adapter body is achieved in accordance with the present invention by a centering ring transverse to the air column and which desirably takes the form of a circular centrally apertured flat plate. The center opening of the plate accommodates not only the fuel tube but also the ignition electrodes which parallel the fuel tube and customarily form part of an ignition electrode-fuel tube sub-assembly removable and replaceable as a unit. Desirably the air is deflected at several points along the course of the air column, a second deflection being obtained at the discharge end of the air tube by a circular ring or flange carried by the head of the air tube assembly transverse to the air column and spaced axially fromthe centering ring so that both the nozzle and the adapter body are located between the planes of the rings.

Other objects and advantages of the invention relate to certain novel structural details and combinations and arrangements of parts apparent in the following detailed description of preferred embodiments representative of the best known mode of practicing the invention, this description being made in connection with the accompanying drawings forming part of the specification.

In the drawings:

Fig. l is a fragmentary vertical sectional view through a heater-burner combination showing in elevation an oil burner having the air tube assembly of the present invention; v

i Fig. 2 is a fragmentary longitudinal section through the air tube assembly of the burner of Fig. l and enlarged with respect to that figure;

Fig. 3 is an end elevation of the air tube assembly, partly in section and with parts broken away and removed, this view being taken substantially in the plane represented by the line 33 of Fig. 2;

v Fig. 4 is a sectional detail taken substantially in I plane represented by the line -4-4 of Fig. 2; and

Fig. 5 illustrates a modification of the head of the air tube assembly and is a fragmentary longitudinal sectional detail taken through the discharge end of such assembly, this view corresponding to the. left end portion a in the residenceor other building in which it is to be p The burner component B is then mounted cantilever fashion on upright front wall 12 of the heater H, the fuel conduit-ignition electrode assembly being inserted into the air tube assembly A as the burner housing 1 is moved into position on supporting studs 14 projecting horizontally from the heater wall 12.

The heater H may be either a boiler or hot air furnace, a fragment of a heater of the latter type being illustrated. The heater H has an inner sheet metal shell or liner comprising an upright cylindrical wall panel 15 and a circular sheet metal bottom 16, the latter being peripherally flanged at 17 for securement to the upright Wall 15. Surrounding the inner shell in spaced relation in the provision of an annular air heating chamber 22 is an outer shell or casing comprising an upright wall which may be circular, square, rectangular or any other desired plan form and which includes the upright supporting wall 12 on which the burner component Bis mounted cantilever fashion. The inner shell panel 15, or at least the The housing 1 of the burner component B is internally partitioned in accordance with known practice to provide an upper fan chamber and a lower air chamber connected by a passage which receives air from the fan chamber and introduces the air tangentially into the air chamber. The electric motor 2 actuates not only the fuel oil pump 3 at one end but also a blower at the other end located in the fan chamber of the housing 1.

A closure plate 23 is disposed across the open face of the casting which constitutes the burner housing 1, this plate having an upper opening through which. air flows into the fan chamber and a lower opening 24 through which the tube structure A receives air from the lower chamber of the housing.

The burner component B is mounted with the closure plate 23 confronting and in spaced parallel relation to the supporting wall 12, the studs 14 carrying spacing sleeves or being formed with locating shoulders for the purpose and base 34 of the air tube structure constituting a spacer for the lower part of the burner component, as will appear. Space thus provided between the wall 12 of the heater and the closure plate 23 of the burner constitutes a passage open about the entire periphery of the housing through which air is drawn into the fan chamber of the housing 1, as described more fully in the co-pending application referred to.

A fluid fuel such as petroleum oil is forced by the pump 3 through a metal tube 25 that terminates at a fitting 26 on the receiving end of the rigid metal fuel tube or conduit 6. j

The air tube structure A constitutes a subassembly whichmay be mounted the heater component H at the time of manufacture. The tube structure is projected through aligned circular openings and in the inner shell panel 15 and the upright supporting wall 12, respectively. A flanged sleeve 28 surrounds the air tube structure in the air chamber 22 of the heater, this sleeve being considerably larger in diameter than the air tube of the burner in the provision of an annular insulating chamber 'that is filled with loose insulation 29. The forward or discharge end of the air tube projects through and has a close fit within a circular opening 30 in the refractory wall 19. of the fire box, the end of the air tube being flush with the inside surface of the fire wall, or substantially The air tube subassembly comprises, a cylindrical'tube 32, a flanged head 33 and a flanged base 34, all made of thin sheet metal, preferably a heat resistant metal such as stainless steel. j

The head 33 and the base 34 are conveniently made as stampings, since the axial lengths of the joint flange 35 on the head and a similar joint flange 43 on the base 34 are not critical factors.

.The burner head 33 is essentially a centrally apertured thin metal dischaving the annular cylindrically shaped outer peripheral flange 35 by means of which the head is connected to the discharge end of the cylindrical air tube body 32 in a press fitted telescopic joint 36. An annular inner marginal portion 37 of the head 33 surrounding central circular discharge outlet 38 is offset axially or inwardly toward the fuel nozzle 7. This ofisetting of the inner peripheral portion 37 of the burner head provides, on the inside of the head, an an nular channel 39 which receives the outer peripheral portion of the air column advancing spirally through the air tube. The received air is deflected not only radially inwardly toward the center of the advancing air column but also rearwardly, the air being guided in such rearward deflection by an annular axially extending wall portion 40 which connects the main annular wall of the burner head and the offset inner peripheral portion 37.

The base 34 comprises a substantially flat annular plate or body portion formed with a plurality of integral radially projecting attaching ears 42. The outer periph cry of the body plate is generally circular except for the cars 42 which are equiangularly spaced about the base periphery and are ofiset from the plane of the body plate.

A circular annular flange 43 is formed integrally about the inner periphery of the body plate and projects axially from the plane of the latter to receive the inner end of the cylindrical air tube body 32 in a press fitted telescopic joint 44. The flange 43 thus defines the circular opening through which the combustion air flows from the base 34 into the tubular body 32 of the air tube structure.

An integral annular flange 45 on the outer periphery of the body plate of the air tube is continuous about the entire periphery of the base plate including the radially projecting attaching ears 42. The flange 4-5, directed axially and opposite to the direction of the inner or joint flange 43, constitutes a spacer between the supporting plate 12 of the heater component H and the burner combetween the burner B and the heater wall 12, and positive pressure is obtained between the annular line contact along the edge 46 of the flange 45 on the air tube base ring and the outside face of the closure plate 23 of the burner housing.

The offsetting of the ear portions 42 of the base 34 toward the: plane of the edge 46 that seals against the genome closure plate 23 separates such ear portions from the outside surface of the upright wall 12 of the heater by clearance spaces one of which is indicated at 47, Fig. 2. The ofiset portions of the ears 42 do not extend radially inwardly as far as the cylindrical flange 43 which secures the base to the tube 32, thereby providing a completely closed or annular surface portion on the base 34 immediately adjacent the cylindrical flange 43, this completely annular portion of the base being held strongly against the wall plate 12 of the heater around the entire perimeter of the heater wall opening 27 in the establishment of a circular seal between the heater wall and the air tube base. The clearances 47 between the ear portions of the base and the heater wall 12 allow the base to be sprung or deformed slightly by screws 48 received through openings 49 in the ears of the base and threaded into the heater wall 12 to secure the air tube assembly in fixed predetermined relation tothe heater structure. The inherent resiliency of the sprung sheet steel of which the stamped base 34 is fabricated maintains the sealing contact between the heater wall 12 about the opening 27 in the latter and the annular portion of the air tube base 34 immediately adjacent the cylindrical flange 43. By this arrangement looseness in the joint is permanently eliminated with attendant noise reduction, since vibrating and rattling of the parts is prevented.

The present construction, in which the cylindrical flange 35 of the stamped stainless steel burner head 33 is telescoped over and tightly embraces the discharge end of the cylindrical stainless steel air tube 32, achieves several desirable results. In assembly the parts can be press fitted together, as in an arbor press, providing good heat conductivity as well as eliminating vibration in use. By performing the telescoping operation in an assembly jig with limiting stops the over-all axial length of the air tube-burner head assembly can be accurately maintained even though the axial lengths of the air tube and of the burner head flange may vary in practice. Having been precisely located in the jig, the burner head flange and the end of the cylindrical air tube embraced by such flange can be conveniently spot welded together at a number of circumferentially spaced points, positively securing the parts together. ,This welding can be done while in the assembly jig or, if desired, the assembly can be removed from the jig and the welding done in a Separate operation, it being understood that the. frictional grip of the burner head flange on the end 'of the air tube at the joint 36 adequately holds the parts in the desired relative axial positions when removed from the jig for use or for the optional spot weldingv operation. In this connection it is significant that end 31 of the air tube 32 is not abutted against the inside of the radial portion of the air tube 33, there being no axial locating of one member against the other. The parts are held permanently in the proper axial relationship only by the frictional grip or spot welding, or by both the frictional grip and the spot welding.

Similarly, at the base end of the air tube the latter is circumferentially and tightly embraced by the cylindrical axially directed flange 43 of the base ring 34 into which the air tube is telescoped and press fitted in assembly. Assembly of the air tube 32 into the base ring flange may be accomplished in an arbor press, vusing a locating jig so as to maintain predetermined over-all axial length for the assembly. Desirably' the telescoping of the burner head 33 and the base ring 34 onto the opposite ends of the air tube 32 may be accomplished simultaneously, using a suitable press and a jig that results in a predetermined over-all axial length of the complete air tube, base ring and burner head assembly. Since the axial length of each of the friction joints 36, 44 normally is several (at least three) times the radial thickness of the metal in the flange and tube comprising the joint it is unnecessary to hold the tube 32 and the head and base flanges 35, 43 to close manufacturing tolerances. Additionally, good heat conductivity prevails between the tube 32 and both'the head and the base. The spot welding of the base ring flange 43 to the air tube 32 augments the frictional grip between the parts at the joint 44 to hold them together in the desired axial relationship. As in the burner head joint, there is no shoulder or other mechanical arrangement for locating the air tube axially relative to the base ring 34, this locating being accomplished by instruments or by the assembly jig mentioned.

In operation the good heat conductivity obtained between the burner head 33 and the cylindrical air tube 32 by reason of the press fitted joint 36 allows heat absorbed by the burner head to be connected directly into the main body of the air tube, the latter being continuously cooled by the spirally advancing air column. The spot welding together of the parts improves the heat conductivity so that the burner head is effectively maintained at a relatively low operating temperature. Furthermore, the relatively thin section of the stainless steel of which the air tube is constructed results in a relatively low heat capacity. Upon starting, the burner head and forward portion of the air tube are brought rapidly to temperature, thus improving combustion characteristics and overall burner efficiency. Upon shutdown, the burner head rapidly loses temperature, eliminating prolonged radiation of heat onto the burner atomizing nozzle and reducing objectionable carbonization of the latter.

Intermediate the ends of.the air tube 32 the advancing column of spirally rotating air is intercepted by a circular air control plate or annular centering ring 50 in the form of a flat stamping of sheet metal such as stainless steel. This control ring or plate is supported in a plane normal to the axis of the tube and the advancing air column as by radial legs 51 of a spider 52 to which the ring is spot welded. This spider has a hub received on the fuel tube 6 for longitudinal sliding movement, being held in adjusted position by a set screw 53 threaded into a radial socket in the hub of the spider and engageable against the fuel tube 6. The outer ends of the spider legs 51 are engageable with the air tube 32 to center the fuel tube 6 on the longitudinal axis of the air tube.

Outer periphery 55 of the air control ring 50 is of slightly less diameter than the inside surface of the air tube 32 so that an annular clearance space 56 allows the outermost portion of the advancing air column in the form of a radially thin cylindrical shell to pass the control ring.

Inner peripheral edge 57 of the control ring 50 is of generally circular shape, being concentric to the circular outer periphery 55 and the axis of the air tube 32. However, suitable provision is made to avoid shorting of the ignition electrodes 8, 9 by the control ring 50 as by cutouts or recesses 58 which allowsuflicient clearance between the ring and the electrodes to prevent arcing. The recesses 58 are not necessary to the functioning of the plate as an air control device, it being understood that other arrangements such as insulators can be used for preventing shorting of the electrodes.

The control ring 50 is spaced in the direction of the oncoming air column from the nozzle 7 so that a portion of the advancing air column is deflected radially before the column passes the plane of nozzle orifice 60, some of the air being deflected outwardly to comrningle with the'outermost radially thin shell portion of the air column and pass the control ring through the relatively narrow annular clearance 56. Y intercepted air which is deflected radially inwardly commingles with the air in the central portion of the column, passing the control ring 50 through the central opening defined by the inner periphery 57. The area of the central opening through the control ring, that is to say, the net or effective opening which includes the areas of the recesses 58 and excludes the areas occupied by the electrodes 8, 9 and the legs and hub of the spider 52, is greater, preferably at least about four times greater than the net or effective area of the outer annularrclearance 57 between the controlgplate periphery 55 and the inside cylindrical surface of the 'airtube 32 to'obtain optimum proportioning of the air flow in the outer shell and central core portions of the air column.

The inward deflection of the advancing air by the control plate 50 creates radial cross currents in the core of the spirally rotating air column, these cross currents being established before the air passes the plane of the fuel projecting orifice 60 in the nozzle 7 and preferably before the air passes the nozzle and nozzle holder 59 and causing turbulence in the air passing over and immediately surrounding the nozzle 7 and also the turned metal nozzle holder 59 by which the nozzle is mounted on the fuel tube 6. The turbulent air about the nozzle and the nozzle holder effectively withdraws heat from the nozzle to prevent the latter'from carbonizing the fuel oil because of heat received from the flame or combustion chamber through the discharge opening 38 of the head.

In addition to the creation of radial cross currents in the advancing air column the control ring 50 creates anrannular quiescent zone within that portion of the air tube 32 located between the plane of the control ring and the head 33 on the forward or discharge end of the air tube. This quiescent zone increases the effectiveness of the burner head 33 in establishment of radial cross currents in the air column at the discharge opening 38. The burner head 33 and the control ring 50 are thus interrelated in that not only do they both create radial cross currents in the advancing air column but the turbulence and flame retention characteristics of the air mass in which burning occurs, which characteristics are obtained by the burner head 33, are improved by the control ring 50. While the exact position of the control ring 50 along the fuel tube6 may be varied to suit the particular characteristics of different burners it is generally preferred to locate the control ring in a plane spaced from the plane of the discharge opening 38 a distance no less than the diameter of the head discharge opening 38 and no greater than the inside diameter of the air tube 32. Thus, a spacing of the control ring from the plane of the discharge opening in the head a distance axially of the air tube which is intermediate the diameter of the head discharge opening and the inside diameter of the air tube achieves optimum performance in the burner.

A relationship also exists between the area of the head discharge opening 38 and the central opening 57 of the control ring 50, it being preferable to have the net area of the opening through the latter approximately equal to the area of the discharge opening 38. Thus the rate of air flow through the control ring central opening is less than the flow rate through the discharge opening 38 of the head 33, it being understood, of course, that not only the air received into the forward part of the air tube 32 through the central opening 57 of the ring but also the air which passes the control ring 50 through the annular clearance 56 is discharged as a comingled stream through the opening 38 of the head.

In Fig. is illustrated a modification in which a-burner head 63 is substituted for the burner head 33' described in connection with the preceding figures, it being understood that all other parts of the burner are essentially the same as before. The burner head 63 comprises a cup shaped stamping of thin sheet metal such as stainless steel having a flat circular wall portion 64 disposed across the forward end of the air tube and an integral cylindricalflange 65. The flange 65 corresponds to the flange 35 In operation, the burner having the head 33 with the offset annular portion 37 andthe annular internal channel 39 exhibits flame retention characteristics somewhat different from those of a burner having the flat faced head 63 illustrated in Fig. 5 although the latter head produces radial cross currents in the air stream discharged from the opening 68. The outermost portions of the advancing spiral air column, intercepted by the burner head 33, as distinguished from the head 63, are not only deflected radially toward the axis of the air tube, but are also reversed relative to the general movement of the air column.

It is thus apparent that the present inventionprovides an improved air tube assembly for pressure atomizing liquid fuel burners and the like, the shaped parts being readily manufactured by conventional stamping procedures from standard flat sheet metal stock and the cylindrical body of the tube being a section of standard tubular stock. Not only is the present air tube assembly cheaper and more easily assembled than prior structures but it also exhibits improved operating characteristics by reason of its control of the air flow to obtain greater turbulence and flame retention, by reason of improved heat conductivity across its joints and by reason of its low heat capacity. Thus, on starting, the air tube comes more rapidly to operating temperature, obtaining increased burner efficiency, and, on stopping, there is less heat retained to be lost through the stack.

Although the best mode of practicing the invention contemplates the combination of the head and the circular air control ring, it is apparent that the control ring can be used to advantage in combination with other burner heads and with air tubes other than of cylindrical shape, these being contemplated variations within the skill of the designer seeking to employ the fundamental principles of the invention.

What I claim and desire to secure by Letters Patent of the United States of America is:

l. A base ring for insertion between the air tube and the main housing of a fluid fuel burner, said ring comprising a thin sheet metal stamping having a substantially flat annular body with a circular inner periphery and an outer non-circular periphery formed to define a plurality of peripherally spaced integral attaching ears, a cylindrical flange formed integrally on and extending laterally from the inner periphery of the flat body for telescoping attachment of the ring to the air tube, an annular non-circular flange formed integrally on and extending laterally from the outer periphery of the flat body to space the flat body from the main housing, the cylindrical and outer flanges being oppositely directed and the outer flange having peripherally spaced bends corresponding to and located at the attaching ears of the flat body, and the ears being formed with apertures adjacent and radially inwardly of the flange bends to receive attaching elements for holding the base ring in place, whereby the bends in the outer flange reinforce the body against distortion under stresses imposed by such attaching elements.

2. A base ring for insertion between the air tube and the main housing of a fluid fuel burner, said ring comprising a thin sheet metal stamping having a substantially flat annular body with a circular inner periphery and an outer periphery formed to define a plurality of peripheral-t ly spaced integral attaching ears, a cylindrical flange formed integrally on and extending laterally from the inner periphery of the flat body for telescoping attachment of the ring to the air tube, an annular flange formed, integrally on and extending laterally from the outer periphery of the flat body to space theflat body from the main housing, the cylindrical and outer flanges being oppositely directed and the outer flange having peripherally spaced bends corresponding to and located at the attaching ears of the flat body, the ears being formed, with apertures adjacent the flange bends to receive at- 'taching' elements for holding the base ring in place, whereby the bends in the outer flange reinforce the body against distortion under stresses imposed by such attaching elements, the body having a completely annular sealing portion adjacent the cylindrical flange for sealing engagement with a heater wall into which the air tube is inserted, and the attaching ears of the body about the apertures being resilient and offset from the plane of the body, whereby the body ears are sprung by attaching elements received in the apertures and tightened to retain the annular sealing portion strongly against such a heater wall.

3. A base ring for insertion between the air tube and the main housing of a fluid fuel burner, said ring comprising a thin sheet metal stamping having a substantially flat annular body with a circular inner periphery and an outer periphery formed to define a plurality of periph erally spaced integral attaching ears, a' cylindrical flange formed integrally on and extending laterally from the inner periphery of the flat body for telescoping attachment of the ring to the air tube, an annular flange formed integrally on and extending laterally from the outer periphery of the flat body to space the flat body from the main housing, the body having areuately curved outer peripheral edge portions extending between the attaching ears, the outer peripheral flange having cylindrically curved portions disposed along the areuately curved edge portions of the body, the body being formed with aperturesin said attaching cars to receive attaching elements for holding the base ring in place, and the outer flange having peripherally spaced bends corresponding in number to and located at the attaching ears radially outwardly of the corresponding apertures.

4. A base ring for insertion between the air tube and the main housing of a fluid fuel burner, said ring comprising a thin sheet metal stamping having a substantially flat annular body with a circular inner periphery and an outer periphery formed to define a plurality of peripherally spaced integral attaching ears, a cylindrical flange formed integrally on and extending laterally from the inner periphery of the flat body for telescoping attachment of the ring to the air tube, an annular flange formed integrally on and extending laterally from the outer periphery of the flat body to space the flat body from the main housing, the body having areuately curved outer eripheral edge portions extending between the attaching ears, the outer peripheral flange having cylindrically curved portions disposed along the areuately curved edge portions of the body, the body being formed with apertures in said attaching ears to receive attaching elements for holding the base ring in place, the cylindrical and the outer flanges being oppositely directed so that the latter is abuttable against the burner housing, and the outer flange having peripherally spaced bends corresponding in number to and located at the attaching ears radially outwardly of the corresponding apertures.

5. A base ring for insertion between the air tube and the main housing of a fluid fuel burner, said ring comprising a thin sheet metal stamping having a substantially flat annular body with a circular inner periphery and an outer periphery formed to define a plurality of peripherally spaced integral attaching cars, a cylindrical flange formed integrally on and extending laterally from the inner periphery of the flat body for telescoping attachment of the ring to the air tube, an annular flange formed integrally on and extending laterally from the outer periphery of the flat body to space the flat body from the main housing, the body having arcuately curved outer peripheral edge portions extending between the attaching ears, the outer peripheral flange having cylindrically curved portions disposed along the areuately curved edge portions of the body, the body being formed with apertures in said attaching ears to receive attaching elements for holding the base ring in place, the outer flange having peripherally spaced bends corresponding in 10 number to and located at the attaching ears radially outwardly of the corresponding apertures, and the attaching ears each being wholly within the surface generated by the outer peripheral flange and continuous from the aperture therein to the outer flange at and on both sides of the adjacent flange bend.

, 6. A base ring for insertion between the air tube and the main housing of a fluid fuel burner, said ring comprising a thin sheet metal stamping having a substantially flat annular 'body with a circular inner periphery and an outer periphery formed to define a plurality of peripherally spaced integral attaching ears, a cylindrical flange formed integrally on and extending laterally from the inner periphery of the flat body for telescoping attachment of the ring to the air tube, an annular flange formed integrally on and extending laterally from the outer periphery of the flat body to space the flat body from the main housing, the body having areuately curved outer peripheral edge portions extending between the attaching ears, the outer peripheral flange having cylindrically curved portions disposed along the areuately curved edge portions of the body, the body being formed with apertures in said attaching ears to receive attaching elements for holding the base ring in place, and the attaching ears being resilient and offset from the plane of the body to permit of deflection under attaching element load.

7. A fluid fuel burner comprising in combination a generally circular sectioned air tube having a receiving end and a discharge end formed with a reduced diameter outlet opening, means supplying air tangentially to the receiving end of the air tube to advance such air through the tube in the form of a circular sectioned spirally rotating column, a nozzle having a discharge orifice, means supplying fluid fuel to the nozzle under pressure, means supporting the nozzle with the nozzle orifice located intermediate the ends of the air tube to project fuel into the air at the discharge end of the air tube, an annular ring shaped substantially flat thin metal air control member, means supporting the air control member Within the air tube in a plane normal to the longitudinal axis of the air tube, the control member having an outer periphery spaced radially inwardly from the air tube to form an annular clearance through which the outermost portions of the air column pass the control member, the control member having an inner periphery defining a central axial opening having an effective area for the passage of air at least four times the area of the annular clearance about the outer periphery of such control member whereby the air in the advancing column divides at the control member with one portion passing through the central opening and another portion passing through the annular clearance, the control ring member being generally of greater radial extent in relation to the section of the air tube in the plane of the ring member than the annular clearance between the outer periphery of such ring member and the tube, and the control member being spaced from the opening in the discharge end of the air tube a distance no less than the diameter of such discharge opening and no greater than the diameter of the air tube and from the nozzle orifice toward the receiving end of the air tube to intercept and deflect a portion of the spirally advancing air before such air passes the nozzle orifice.

8. In a fluid fuel burner of the type comprising a generally circular sectioned air tube through which air for combustion is advanced spirally as a column from a receiving end to a discharge end having a circular outlet opening of less diameter than the air tube, a nozzle having an orifice disposed to project fuel into the air at'the discharge end of the tube, and a conduit extending longitudinally through the air tube and connected to the nozzle to supply fuel to the latter, the combination of an annular substantially flat thin metal ring member disposed within the air tube transverse to the longitudinal axis of the air ,tube and the advancing air column for 11 intercepting the latter and controlling the air flow, said annular air control ring member being mounted on the fuel supply conduit and located in a plane spaced from the opening in the discharge end of the air tube a dis tance no less than the diameter of such discharge opening and no greater than the diameter-of the air tube and from the nozzle orifice in the direction of the receiving end of the air tube, said ring member having a central opening substantially concentric to the axis of the air tube and an outer peripheral edge spaced from the air tube wall to form an annular clearance through which the outermost portions of the advancing air column pass the annular control ring member, the control ring member being generally of greater radial extent in relation to the section of the air tube in the plane of the ring member than the annular clearance between the outer periphery of such ring member and the tube, whereby air advancing in those portions of the air column located radially inwardly of the cylindrical surface generated by the outer periphery of the control member is intercepted by the control member and radially deflected, some outwardly to commingle with and create cross currents in the air flowing through the annular clearance and some inwardly to commingle with and create cross currents in the air flowing through the central opening, and said central opening having an effective area for the passage of air at least four times the area of the annular clearance about the outer periphery of said control member.

9. In a fluid fuel burner of the type comprising a generally circular sectioned air tube through which air for combustion is advanced spirally as a column from a receiving end to a discharge end having a circular outlet opening of less diameter than the air tube, a nozzle having an orifice disposed to project fuel into the air at the discharge end of the tube, and a conduit extending longitudinally through the air tube and connected'to the nozzle to supply fuel to the latter, the combination of a spider having a central hub received on and adjustable along the length of the fuel conduit and an air control member mounted on the spider, the spider having radial legs projecting outwardly from the hub and engageable with the air tube to center the fuel conduit in the latter, the control member comprising an annular ring and being secured to the spider legs outwardly of the hub for movement with the spider to-diiferent positions along the length of the fuel conduit, the ring member having a central opening concentric to the fuel conduit and an outer periphery spaced from the air tube to form an annular clearance through which the outermost portio-ns of the spirally advancing air passes the control ring, said central opening having an effective area for the passage of air at least four times the area of the annular clearance about the outer periphery of such control memher, the control ring member being generally of greater radial extent in relation to the section of the air tube in the plane of the ring member than the annular clearance between the outer periphery of such ring member and the tube, and said ring member in all positions of adjustment being wholly spaced axially of the air tube from the opening in the discharge end of the air tube a distance no less than the diameter of such discharge opening and no greater than the diameter of the air tube and from the discharge orifice of the nozzle toward the receiving end of the air tube.

10. In a fluid fuel burner of the type comprising a generally circular sectioned air tube through which air for combustion is advanced spirally as a column from a receiving end to a discharge end having a circular outlet opening of less diameter than the air tube, a nozzle having an orifice disposed to project fuel into the air at the discharge end of the tube, and a conduit extending longitudinally through the air tube and connected to thesnozzle to supply fuel to the latter, the combination of a spider having a central hub received'on and adjustable along the lengthof the fuel conduit and an air control member mounted on the spider, the spider having radial legs projecting outwardly from the hub and engageable with the air tube to center the fuel conduit in the latter, the control member comprising a substantially flat sheet metal ring disposedin a plane normal to the 'airvtuhe axis'andsecured 'to the legs of the, spider radially;out wardly of the hub for movement withthe spider to different positions along the length of the fuel conduit, the ringtmember having a central opening concentric to the fuel conduit and an outer periphery spaced from the air tube to form an annular clearance through which the outermost portions of the spirally advancing air passes the control ring, said, central opening havingian effective area for the passage of air at least four times the area of the annular clearance about the outer periphcry of such control member, the control ring member being generally of greater radial extent in relation to the section of the air tube in the plane'of the ring member than the annular clearance between the outer periphery of such ring member and the tube, and said ring member in all positions of adjustment being wholly spaced axially of the air tube from the opening in the discharge end of the air tube a distance no less than the diameter of such discharge opening and no greater than the diameter of the air tube and from the discharge orifice of the nozzle toward the receiving end of the air tube.

11. In a fluid fuel burner of the type comprising a generally circular sectioned air tube through which air for'combustion isadvanced spirally as a column from a receiving end to a'discharge end, a nozzle having an orifice disposed to project fuel into the air at the dis-' charge end of the tube, and a conduit extending longitudinally through the air tube and connected to the nozzle to supply fuel to the latter, the combination of a spider having a central hub received on and adjustable along the length of the fuel conduit and an air control member mounted on the spider, the spider having radial legs projecting outwardly from the hub and engageable with the air tube to center the fuel conduit in the latter, the control member comprising an annular ring and being'secured to the spider legs outwardly of the hub for movement with the spider to different positions along the length of the fuel conduit, the ring member having a central opening concentric to the fuel conduit and an outer periphery spaced from the air tube to form an annular clearance through which the outermost portions of the spirally advancing air passes the control ring, the control ring member being generally of greater radial extent in relation to the section of the air tube in the plane of the ring member than the annular clearance between the outer periphery of such ring member and the tube, the effective area of the annular clearance being small relative to the effective area of the central opening of the ring member, whereby most of the advancing air intercepted by the ring member is deflected radially in wardly to pass the latter through the central opening, and said ring member in all positions of adjustment being .wholly spaced axially of the air tube from the opening in the discharge end of the air tube a distance no less than the diameter of such discharge opening and no greater than the diameter of the air tube and from the discharge orifice of the nozzle toward the receiving end of th air tube. 7

12. A fluid fuel burner comprising in combination a generally circular sectioned air tube having a receiving end and a discharge end, means supplying air'tangentially to the receiving end of the air tube to advance such air through the tube in the form of a circular sectioned spirally rotating column, a nozzle having adischarge orifice, means supplying fluid fuel to the nozzle under pressure, means supporting the nozzle with the nozzle orifice located intermediate the ends of the air tube to project fuel into the air at the discharge end of the air tube, an annular ring shaped substantially flat thin metal control member, means supporting the air control 13 member within the air tube in a plane normal to the longitudinal axis of the air tube, a head comprising an annular ring shaped member of thin sheet metal disposed across the discharge end of the air tube, the head and the control ring each having a flat annular portion formed with a central aperture symmetric about the longitudinal axis of the air tube and free of transverse obstructions, the apertures of the head and the control ring being approximately equal in effective area and disposed in parallel planes spaced apart a distance less than the diameter of the air tube at the control ring plane, the air control member having a circular outer periphery of less diameter than the air tube to form a peripheral clearance space through which the outermost portions of the spirally advancing air column passes the control member, the central aperture of the control member being of greater area than the peripheral clearance space and the nozzle being located with its discharge orifice I intermediate the planes of the head and control ring apertures.

13. A fluid fuel burner comprising in combination a generally circular sectioned air tube having a receiving end and a discharge end, means supplying air tangentially to the receiving end of the air tube to advance such air through the tube in the form of a circular sectioned spirally rotating column, a nozzle having a discharge orifice, means -supplying fluid fuel to the nozzle under pressure, means supporting the nozzle with the nozzle orifice located intermediate the ends of the air tube to project fuel into the air at the discharge end of the air tube, an annular ring shaped substantially flat thin metal air control member, means supporting the air control member within the air tube in a plane normal to the longitudinal axis of the air tube, a head comprising an annular ring shaped member of thin sheet metal disposed across the discharge end of the air tube, the head and the control ring each being formed with a central circular aperture concentric to the longitudinal axis of the air tube,

- the apertures of the head and the control ring being substantially free of transverse obstructions and substantially equal in efiective area and being in parallel planes spaced apart a distance greater than the diameter of the head aperture and less than the diameter of the air tube at the control ring, the air control member having a circular outer periphery of less diameter than the air tube to form a peripheral clearance space through which the outermost portions of the spirally advancing air column passes the control member, the central aperture of the control member being of greater area than the peripheral clearance space and the nozzle being located with its discharge orifice intermediate the planes of the head and control ring apertures. 1

14. A fluid fuel burner comprising in combination a generally circular sectioned air tube having a receiving end and a discharge end, means supplying air tangentially to the receiving end of the air tube to advance such air through the tube in the form of a circular sectioned spirally rotating column, a nozzle having a discharge orifice, means supplying fluid fuel to the nozzle under pressure, means supporting the nozzle with the nozzle orifice located intermediate the ends of the air tube to project fuel into the air at the discharge end of the air tube, an annular ring shaped substantially flat thin metal air control member, means supporting the air control member within the air tube in a plane normal to the longitudinal axis of the air tube, the control member having an outer. periphery spaced radially inwardly from the air tube to form an annular clearance through which the outermost portions of the air column pass the core trol member, the control member having an inner periphery defining a central axial opening whereby the air in the advancing column divides at the control member with one portion passing through the central opening and another portion passing through the annular clearance, a thin sheet metal head disposed across the discharge end of the air tube and having a circular opening concentric to the axis of the air tube, the openings of the control member and the head being substantially free of transverse obstructions and substantially equal in eifective area and being located in parallel planes spaced apart a distance less than the diameter of the air tube at the control member, and the nozzle orifice being disposed intermediate the planes of the openingsin the control member and the head, whereby air deflected radially inwardly by the control member flows through the central opening of the latter and provides a turbulent core of air traveling axially through that portion of the air tube extending between the planes of said openings and surrounding the nozzle, and whereby the spirally rotating outermost portions of the air column after passing the control member through said annular clearance are deflected radially inwardly by the head to enter and commingle with the turbulent core of air as the latter is discharged from the air tube through the head opening.

15. In a fluid fuel burner of the type having a generally circular sectioned air tube through which air for combustion is advanced helically, a head on one end of the air tube defining a circular opening through which the air is discharged, a nozzle inside the air tube having an orifice disposed to project fuel toward the head opening and into air being discharged, said head comprising a one piece thin metal stamping having a pair of concentric inner and outer cylindrically shaped portions integrally connected by a first flat ring portion and a second flat ring portion extending radially inwardly from the inner cylindrical portion, the outer cylindricalportion having telescopic interfitting engagement with the air tube to support the head on the tube, the cylindrically shaped portions being separated by an annular channel open toward air advancing in the tube toward said one end of the latter, and the second fiat ring portion being axially spaced toward the nozzle from the first ring portion and having an inner thin edged periphery defining the discharge opening.

References Cited in the file of this patent UNITED STATES PATENTS 2,090,566 Andler Aug. 17, 1937 2,360,503 Livar Oct. 17, 1944 2,405,196 Elliot Aug. 6, 1946 2,456,930 DeLancey Dec. 21, 1948 2,502,664 Nest Apr. 4, 1950 2,531,538 Smith Nov. 28, 1950 2,546,409 Ritter Mar. 27, 1951 2,553,520 Neiman May 15,- 1951 2,599,153 Beckett June 3, 1952 2,676,648 Dennis Apr. 27, 1954 2,681,693 Logan June 22, 1954 2,790,490 Smith Apr. 30, 1957 FOREIGN PATENTS 168,865 Switzerland July 16, 1934 OTHER REFERENCES Kooiker Abstract, 98,999, filed June 14, 1949, published 650 0.6. 599, Sept. 11, 1951. 

